JPH05151837A - Ceramic superconductive conductor - Google Patents

Abstract

PURPOSE:To provide a ceramic superconductive conductor of high Ic which has simple structure and is hard to deteriorate its superconductive characteristic even when repeatedly bent. CONSTITUTION:A tape-like composite body 4 which has a ceramic superconductive layer 2 within a metal later 1 and is lengthwise provided with the desired number of slits 3 each having a predetermined length, are wrapped in the desired number of sheets around the circumference of a core member 5 such as a metal pipe and a round bar.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramics superconducting conductor applicable to high-voltage electric power transportation such as electric power cables, etc., and in particular, the structure of the conductor is simple and the superconducting characteristic is less deteriorated even against bending strain. The present invention relates to a ceramic superconducting conductor having high Ic.

[0002]

2. Description of the Related Art Ceramic superconductors having a Tc exceeding the temperature of liquid nitrogen, such as Y type, Bi type and Tl type, are known. It has been studied to form such ceramic superconductors into various shapes for the purpose of utilization in various fields. For example, a metal sheath method is generally used when molding into a wire rod. This is to fill a metal pipe with ceramic raw material that can be a superconductor to form a composite billet, and then reduce the cross-section of the composite billet to finish it into a composite wire rod with a desired shape and size. To do.

The shape of the wire obtained by this method is
For example, there are round, elliptical, quadrangular, and tape-shaped cross sections. In addition, various prototypes of multi-core wire rods obtained by bundling a plurality of these wire rods, multi-layer wire rods having a ceramic superconductor layer arranged in a metal layer in a concentric cylindrical shape or in a spiral shape, and the like have been studied.

In this case, as the material of the metal used, a material having excellent thermal conductivity and electrical conductivity, such as Ag, Ag alloy, Cu, Cu alloy, etc., is suitable, but in view of oxygen permeability and oxidation resistance. In many cases, Ag and Ag alloys are used. Further, as the cross-section reduction working method, the conventional plastic working method such as extrusion, rolling, drawing, swaging, etc. is applied as it is according to the shape of the obtained wire.

In recent years, a ceramic superconducting conductor obtained by winding a desired number of the thus obtained tape-shaped composite material around a core material such as a metal pipe or a round bar is wrapped around the core material such as a power cable. It is considered to be applied to. Specifically, as shown in FIG. 4 (a), a tape-shaped composite D having a narrow width is spirally wrapped and wrapped using a large number of tapes per layer, and the tape-shaped composite D is laminated in a multilayer form. As shown in FIG. 3B, one or two tape-shaped composites D each having a wide width are spirally wound and wrapped by using about one or two layers, and the tape-shaped composite D is laminated in multiple layers.

In the ceramic superconducting conductor shown in FIG. 4 (b), since the tape-shaped composite body D wrapped around the core material A has a wide width, the cross-sectional area of the ceramic superconductor C inside increases.
There are advantages that the Ic can be improved and that the configuration is easy.

[0007]

When the ceramics superconducting conductor shown in FIG. 4 is actually used as a cable for electric power transportation, it is necessary to wind the ceramics superconducting conductor around a drum in terms of workability in manufacturing, transportation and installation. There is. Therefore, it is desirable that the superconducting characteristics do not deteriorate even if the ceramic superconducting conductor is repeatedly bent several times in consideration of winding on a drum, bending by rewinding, bending during construction work, and the like.

However, in the ceramic superconducting conductor shown in FIG. 4 (b), since the tape-shaped composite D has a wide width, it has a high Ic but is poor in flexibility and can effectively disperse strain when bending is applied. However, there was a problem that Ic was lowered due to local deformation or breakage.

An object of the present invention is to provide a ceramic superconducting conductor having a high Ic, which has a simple structure and is hardly deteriorated in superconducting characteristics even if it is repeatedly bent.

[0010]

The present invention was obtained as a result of various experimental studies for improving the above-mentioned drawbacks.
As shown in (a) to (d), a tape-shaped composite body 4 having a ceramics superconductor layer 2 in a metal layer 1 and provided with a desired number of slits 3 of a predetermined length in the longitudinal direction is formed of a metal. It is characterized in that a desired number of cores 5 such as pipes and round bars are wrapped around the core 5 and arranged.

In FIG. 1 (a), a plurality of slits 3 having substantially the same length as the tape-shaped composite 4 are provided at a predetermined interval in the tape-shaped composite 4, and the tape-shaped composite 4 is spirally formed one layer at a time. An example in which the tape-shaped composite body 4 is wrapped and wrapped in such a manner that it is laminated and arranged in multiple layers, and FIG. 2B shows that two tape-shaped composite bodies 4 provided with a plurality of the long slits 3 as described above become one layer. An example in which the tape-shaped composite body 4 is wrapped around and wrapped in a multi-layered manner, and the tape-shaped composite body 4 in FIG. 3A is provided with a plurality of short slits 3 at predetermined intervals is used. For example, FIG. 3D is an example in which the tape-shaped composite body 4 of FIG. 1B is provided with a plurality of short slits 3 at predetermined intervals.

In addition to the metal pipe, the core material 5 may be, for example, a metal round bar or a metal pipe which is corrugated to have flexibility. There is no restriction on the winding pitch of the tape-shaped composite body 4 which is spirally arranged on the outer periphery of the core material 5, and can be selected in consideration of the maximum bending strain, the outer diameter of the ceramic superconducting conductor, and the like. Further, the number of sheets per layer and the number of layers to be laminated are not particularly limited, and various selections can be made according to the current capacity. The ceramic superconducting conductor of the present invention is particularly suitable for use when the width of the tape-shaped composite 4 is wide and the number of windings per layer is about 1 or 2.

The length, width, number, and position of the slits 3 formed in the tape-shaped composite body 4 are not particularly limited, and can be variously determined according to the size of the composite body 3 and the use conditions. However, it is desirable that there is at least one slit 3 in the width direction at any position in the longitudinal direction of the tape-shaped composite body 4. For example, as shown in FIG. 2 (a), a plurality of slits 3 continuous in the longitudinal direction of a tape-shaped composite body 4 are provided in parallel, and a predetermined length as shown in FIGS. 2 (b) and 2 (c). There are a plurality of slits 3 arranged in a staggered arrangement at predetermined intervals in the vertical and horizontal directions. If the width of the slit 3 is too wide, a large amount of the ceramic superconductor layer 2 is scraped off, and the decrease in Ic due to this loss cannot be ignored. As a result, the superconducting property is deteriorated, so that it is desirable to be as narrow as possible.

An example of the method for manufacturing the ceramic superconducting conductor of the present invention will be described. The conventional method can be directly applied to the production of the tape-shaped composite body 4. For example, a metal pipe-shaped billet is filled with a raw material capable of forming a ceramics superconductor to form a composite billet, which is subjected to cross-section reduction processing to produce a tape-shaped composite body 4 having a predetermined shape and size. When the width of the tape-shaped composite body 4 is relatively wide, it is preferable to use a composite billet having a rectangular cross section. Then, the slit 3 having a desired length is formed in the tape-shaped composite body 4 obtained by this method in parallel with the longitudinal direction. In this case, for example, a gear-shaped cutter may be used, or punching or the like may be performed.

As shown in FIGS. 1 (a) to 1 (d), the tape-shaped composite body 4 having the slits 3 thus formed is wrapped around the core material 5 by a desired number of layers and laminated by a desired number of layers. To do. Further, if necessary, a metal tape may be pressed and wound on it. Then, heat treatment is performed under predetermined conditions to obtain a ceramics superconducting conductor (W &
R method). Alternatively, the tape-shaped composite body 4 may be heat-treated before being wound around the core material 5 and placed on the outer periphery of the core material 5 to produce a ceramics superconducting conductor (R & W).
Law). Further, in order to protect the ceramic superconducting conductor, it is also within the scope of the present invention to insert it into a corrugated tube of Fe, SUS, Cu or the like.

[0016]

In the ceramic superconducting conductor of the present invention, when the tape-shaped composite body 4 is wrapped around the core material 5 as shown in FIG. 1, a large number of slits 3 are formed on the outer peripheral surface of the ceramic superconducting conductor. As in the case where a large number of tape-shaped composite bodies 4 each having a narrow width are arranged in each layer, the flexibility is improved, and the superconducting characteristics are not significantly deteriorated even when bending distortion is applied to the obtained ceramic superconducting conductor. Moreover, slit 3
Ceramic superconductor layer 2 that is scraped off when forming
The decrease in Ic due to the quantitative loss of is not so large as when a large number of tape-shaped composite bodies 4 having a narrow width are arranged, and thus has a high Ic.

[0017]

Example 1 An example of the ceramic superconducting conductor of the present invention will be described. First, Bi ₂ O ₃ , PbO, SrCO
Primary raw material powders such as ₃ , CaCO ₃ and CuO in a molar ratio of B
i: Pb: Sr: Ca: Cu = 1.6: 0.4: 2:
Mix in a ratio of 2: 3, mix, and then in air 800
It was calcined at 100 ° C. for 100 hours and further pulverized to prepare a calcined powder. After this was CIP molded, it was inserted into an Ag pipe with a square cross-section to form a composite billet, which was subjected to cross-section reduction processing and rolling processing to a width of about 60 mm (width 56 mm of the ceramic superconductor layer 2) and thickness. A 0.25 mm tape-shaped composite 4 was prepared. Five continuous slits 3 were formed in the tape-shaped composite body 4 in the longitudinal direction as shown in FIG. At this time, the length a of both ends of the tape-shaped composite 4 is
10 mm, the distance b between adjacent slits 3 = 10 mm,
The width c of each slit 3 is 0.1 mm.

On the other hand, an Ag pipe (core material 5) having an outer diameter of 20 mmφ and an inner diameter of 16 mmφ was produced, and was corrugated. The tape-shaped composite body 4 was wrapped around the outer periphery of the core material 5 in a spiral shape with a pitch of 1 m, and a total of 10 layers were laminated. This was heat-treated in air at 840 ° C. for 100 hours to prepare a ceramics superconducting conductor. As a result of measuring Ic in liquid nitrogen under an environment of 0 magnetic field in a state where this superconducting conductor was bent to have a radius of curvature of 1 m, 268
The excellent characteristics of (A) were obtained. Incidentally, Ic was 270 (A) when no bending was applied to this ceramic superconducting conductor, and it was found that the present example maintains excellent superconducting characteristics against bending strain.

[0019]

Example 2 A composite billet was produced by using the same calcined powder and Ag pipe as those of Example 1, and was subjected to a cross-section reduction process and a rolling process to obtain a width of about 30 mm (width 26 of the superconductor).
mm), and a tape-shaped composite body 4 having a thickness of 0.25 mm was produced. As shown in FIG. 3B, slits 3 of appropriate length were formed in five rows in the width direction, and slits 3 in adjacent rows were slightly shifted in the longitudinal direction to form a taper array on the tape-shaped composite body 4. At this time, the length a of both ends of the tape-shaped composite 4 is 1
0 mm, spacing b between rows of slits 3 = 5 mm, width c of slits 3 = 0.1 mm, length d of each slit 3 = 20 m
m, the distance e between the slits 3 in the same row is 5 mm.

The tape-shaped composite 4 was wrapped around the outer periphery of the core material 5 of Example 1 in a spiral shape with a pitch of 80 cm using two sheets per layer, and a total of 10 layers were laminated.
This was heat-treated in the air at 840 ° C. for 100 hours to produce a ceramics superconducting conductor. As a result of measuring Ic in an environment of 0 magnetic field in liquid nitrogen with the superconducting conductor bent to have a radius of curvature of 1 m, excellent characteristics of 285 (A) were obtained. By the way, Ic is 288 (A) when this ceramic superconducting conductor is not bent.
Therefore, it was found that the present example also maintains excellent superconducting characteristics against bending strain.

[0021]

[Comparative Example 1] For comparison, a slit 3 is formed in the tape-shaped composite body 4.
A ceramic superconducting conductor was obtained in the same manner as in Example 1 by using the material without the element, and the same experiment as in Example 1 was repeated. As a result, Ic was 215 (A), which was 270 (A) in Example 1. In comparison, the characteristics are significantly deteriorated.

[0022]

[Comparative Example 2] For comparison, a slit 3 is formed in the tape-shaped composite body 4.
A ceramic superconducting conductor was obtained in the same manner as in Example 2 by using a material not provided with, and the same experiment as in Example 2 was repeated. As a result, Ic was 212 (A). The deterioration of the characteristics is remarkable as compared with A).

[0023]

The ceramic superconducting conductor of the present invention has good flexibility because the slits 3 are provided in the longitudinal direction of the tape-shaped composite body 4, the characteristics are hardly deteriorated even when bending strain is applied, and the tape shape is wide. Since the complex 4 can be used, the structure is simple and easy to manufacture, and the high Ic is obtained.

[Brief description of drawings]

1A, 1B, 1C and 1D are perspective views showing various examples of a ceramics superconducting conductor of the present invention.

2 (a), (b) and (c) are plan views showing various examples of a tape-shaped composite used in the ceramics superconducting conductor of the present invention.

3A is a detailed explanatory view showing an example of a slit of the tape-shaped composite body in the ceramics superconducting conductor of the present invention, and FIG. 3B is a detailed explanatory view showing another example of the slit of the tape-shaped composite body.

FIG. 4A is a perspective view showing an example of a conventional ceramics superconducting conductor, and FIG. 4B is a perspective view showing another example of a conventional ceramics superconducting conductor.

[Explanation of symbols]

 1 Metal Layer 2 Ceramics Superconductor Layer 3 Slit 4 Tape-shaped Composite 5 Core Material

Front page continuation (72) Inventor Tsukushi Hara 2-4-1 Nishitsujigaoka, Chofu-shi, Tokyo Inside TEPCO Ltd. Technical Research Institute (72) Hideo Ishii 2-4-1 Nishitsujigaoka, Chofu-shi, Tokyo TEPCO Technical Research Institute Co., Ltd.

Claims (1)

[Claims] 1. A ceramic superconductor layer 2 in a metal layer 1.
And a tape-shaped composite body 4 having a desired number of slits 3 having a predetermined length in the longitudinal direction is arranged on the outer periphery of a core material 5 such as a metal pipe or a round bar so as to cover the outer periphery of the core material 5. Characteristic ceramic superconducting conductor.